package engine

import (
	"path/filepath"
	"strings"
	"testing"

	"github.com/cdnutter/playlink/internal/store"
)

func enableApprox(t *testing.T, ev *env) {
	t.Helper()
	ev.pair.ApproxMatching = true
	ev.pair.ApproxThreshold = 85
	if err := ev.st.SavePair(ctx, &ev.pair); err != nil {
		t.Fatal(err)
	}
}

// The user's example: the master album has disc folders, the slave does not.
func TestApproxDiscFolderUpgrade(t *testing.T) {
	ev := setup(t, false)
	master := ev.write(ev.master, "Andrew Lloyd Webber/Cats/Disc 02/07 Memory.flac", "lossless")
	ev.write(ev.master, "Andrew Lloyd Webber/Cats/Disc 01/07 Macavity.flac", "other")
	ev.write(ev.master, "Andrew Lloyd Webber/Evita/03 Memory.flac", "same title, other album")
	ev.write(ev.slave, "Andrew Lloyd Webber/Cats/07 Memory.mp3", "lossy")

	// Off by default: the title exists on two albums, so nothing matches.
	ev.scan()
	if m := ev.match("Andrew Lloyd Webber/Cats/07 Memory.mp3"); m.Status != store.StatusUnmatched {
		t.Fatalf("approximate matching must be opt-in, got %s/%s", m.Status, m.Kind)
	}

	enableApprox(t, ev)
	ev.scan()
	m := ev.match("Andrew Lloyd Webber/Cats/07 Memory.mp3")
	if m.Kind != store.KindApprox || m.Status != store.StatusSimilar || m.RelMaster != "Andrew Lloyd Webber/Cats/Disc 02/07 Memory.flac" {
		t.Fatalf("unexpected match %s %s -> %s", m.Status, m.Kind, m.RelMaster)
	}
	if !strings.Contains(m.Reason, "disc folder ignored") || !strings.Contains(m.Reason, "track 07 matches") {
		t.Fatalf("reason should explain the match, got %q", m.Reason)
	}

	// Linking upgrades the slave: it gets the master's FLAC in its own folder.
	if _, err := ev.e.Link(ctx, m.ID, LinkOptions{}); err != nil {
		t.Fatal(err)
	}
	upgraded := filepath.Join(ev.slave, "Andrew Lloyd Webber/Cats/07 Memory.flac")
	if !sameInode(t, master, upgraded) {
		t.Fatal("slave should now hold a hardlink of the master FLAC")
	}
}

func TestApproxTitleVariations(t *testing.T) {
	ev := setup(t, false)
	enableApprox(t, ev)
	ev.write(ev.master, "Band/Album/CD1/03 - Dont Stop Believin.flac", "a")
	ev.write(ev.slave, "Band/Album/3 Don't Stop Believing.mp3", "b") // typo-level difference
	ev.write(ev.master, "Band/Album/CD1/04 - Song.flac", "c")
	ev.write(ev.slave, "Band/Album/04 Song (Live).mp3", "d") // different version: must not match
	ev.write(ev.master, "Band/Album/CD2/05 Totally Different.flac", "e")
	ev.write(ev.slave, "Band/Album/05 Something Else.mp3", "f") // too dissimilar
	ev.scan()

	if m := ev.match("Band/Album/3 Don't Stop Believing.mp3"); m.Kind != store.KindApprox {
		t.Fatalf("near-identical title should match approximately, got %s", m.Kind)
	}
	if m := ev.match("Band/Album/04 Song (Live).mp3"); m.Status != store.StatusUnmatched {
		t.Fatalf("live version must not match the studio track, got %s -> %s", m.Kind, m.RelMaster)
	}
	if m := ev.match("Band/Album/05 Something Else.mp3"); m.Status != store.StatusUnmatched {
		t.Fatalf("dissimilar titles must not match, got %s -> %s", m.Kind, m.RelMaster)
	}
}

func TestApproxAmbiguousIsLeftAlone(t *testing.T) {
	ev := setup(t, false)
	enableApprox(t, ev)
	// Two discs each carry an equally good candidate: refuse to guess.
	ev.write(ev.master, "Band/Album/Disc 1/Anthem.flac", "a")
	ev.write(ev.master, "Band/Album/Disc 2/Anthem.flac", "b")
	ev.write(ev.slave, "Band/Album/Anthem.mp3", "c")
	ev.scan()
	if m := ev.match("Band/Album/Anthem.mp3"); m.Status != store.StatusUnmatched {
		t.Fatalf("ambiguous candidates must not be matched, got %s -> %s", m.Kind, m.RelMaster)
	}
}

func TestApproxAlbumFolderRename(t *testing.T) {
	ev := setup(t, false)
	enableApprox(t, ev)
	ev.write(ev.master, "Cast/Cats (Original London Cast)/Disc 2/07 Memory.flac", "a")
	ev.write(ev.slave, "Cast/Cats/07. Memory.mp3", "b")
	ev.scan()
	m := ev.match("Cast/Cats/07. Memory.mp3")
	if m.Kind != store.KindApprox || !strings.Contains(m.Reason, "different album folder") {
		t.Fatalf("should match across album folder names, got %s %q", m.Kind, m.Reason)
	}
}

func TestTitleScore(t *testing.T) {
	cases := []struct {
		a, b string
		min  float64
		max  float64
	}{
		{"07 Memory.flac", "07 Memory.mp3", 1, 1},
		{"07 Memory.flac", "08 Memory.mp3", 0.9, 0.96},
		{"Memory.flac", "Memory (Live).flac", -1, -1},
		{"Song (Remix).flac", "Song (Remix).mp3", 1, 1},
		{"Love.flac", "Love Story.flac", 0, 0.6},
		{"Memory from Cats.flac", "Memory from Cats Remastered.flac", 0.85, 1},
	}
	for _, c := range cases {
		got := titleScore(parseTitle(c.a), parseTitle(c.b))
		if got < c.min-1e-9 || got > c.max+1e-9 {
			t.Errorf("titleScore(%q, %q) = %.3f, want [%.2f, %.2f]", c.a, c.b, got, c.min, c.max)
		}
	}
	if k := albumKey("A/Cats/Disc 02/07 Memory.flac"); k != "a/cats" {
		t.Errorf("albumKey = %q", k)
	}
	if k := albumKey("A/Cats/CD2 - Bonus/x.flac"); k != "a/cats" {
		t.Errorf("albumKey = %q", k)
	}
}